25306640 has 40 divisors (see below), whose sum is σ = 59293080. Its totient is φ = 10044416.

The previous prime is 25306627. The next prime is 25306657. The reversal of 25306640 is 4660352.

It can be written as a sum of positive squares in 4 ways, for example, as 6885376 + 18421264 = 2624^2 + 4292^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9806 + ... + 12114.

It is an arithmetic number, because the mean of its divisors is an integer number (1482327).

Almost surely, 2^25306640 is an apocalyptic number.

25306640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25306640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29646540).

25306640 is an abundant number, since it is smaller than the sum of its proper divisors (33986440).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

25306640 is a wasteful number, since it uses less digits than its factorization.

25306640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2459 (or 2453 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 26.

The square root of 25306640 is about 5030.5705441828. The cubic root of 25306640 is about 293.5924134383.

Adding to 25306640 its reverse (4660352), we get a palindrome (29966992).

The spelling of 25306640 in words is "twenty-five million, three hundred six thousand, six hundred forty".